Unless you really need the 802.11b and Bluetooth, consider the iPaq 1935/45. Same size as the 4150, but cheeper as they lack 802.11b. One other downgrade in this is the processor, to a 200mhz, but that should still be plenty for GPS navigation. Retail on the 1935 is $200 after a $50 rebate. The 1945 is $300, and has bluetooth built in, as well as a larger flash ROM, allowing for larger OS upgrades in the future, or more protected file storage.